I have a my personal addon with simple UI customization. Only thing that doesn't work correctly is the resized ObjectiveTrackerFrame.
1. Whenever a passenger mount is used, it moves left.
2. When the ObjectiveTrackerFrame is closed using the little arrow-button, the background texture stays.
...(code hiding minimap buttons and moving BuffFrame) ...
ObjectiveTrackerFrame:SetWidth(MinimapCluster:GetWidth() * 1.8)
local tex = ObjectiveTrackerFrame:CreateTexture(nil, "OVERLAY")
tex:SetColorTexture(0, 0, 0, 0.2)
I'm not really a coder, I just fumble around, so if someone could help me out ...